1. Field of the Invention
The present invention relates to hydraulic machines and more specifically to the members of such machines placed in direct contact with the flow of water whose energy is to be converted.
2. Description of the Related Art
For the purposes of the present invention, a hydraulic machine can be a turbine, a pump, or a pump/turbine, used, for example, in an electricity generating plant. In the case of a turbine, the machine is placed downstream of a pipe supplied directly by a watercourse or from a reservoir into which one or more watercourses discharge. Depending on the nature of the ground through which the watercourse flows and the meteorological conditions, the water supplied to the machine may contain abrasive particles such as sand or sediment. When these abrasive particles pass through the turbine, they wear the surfaces which are wetted by the flow of water, making it necessary to repair or replace these surfaces at regular intervals. These repairs make the operating costs of the hydraulic machine relatively high, due to the cost of the spare parts and the downtime of the machine.
There is consequently a requirement to increase the durability of the members of hydraulic machines subjected to the action of abrasive particles and to facilitate the repair of worn areas of these members.